1. Field of the Invention
The present invention relates to a banding packing machine and more particularly to a controller in a banding packing machine which controls cutting, welding and the like for binding a band in a predetermined timed cycle.
2. Description of the Prior Art
In an automatic or semi-automatic banding packing machine, a band led from a band reel is wound upon an object to be packed and is then clamped, and subsequently, is returned to the band feeding side and is tightened. Then, a bound portion of the band is melted by a heater almost simultaneously with the cutting and is then bonded by means of a press. These operations are carried out continuously and instantaneously in one cycle.
In such a banding packing machine, a control portion utilizing a cam is provided to precisely carry out the operations. The control portion controls the timing of the operations of the band packing machine. More specifically, a plurality of cams are provided on one cam shaft of the control portion. When the cams are rotated with the cam shaft, cam followers corresponding to the cams are moved vertically so that a plurality of members carry out their predetermined operations, such as clamping, return, tightening and the like.
When a large number of operations are to be thus carried out continuously in a short time period, the band is insufficiently gripped and the band cannot be sufficiently returned if member positions become shifted during the operation of the cam and the cam follower, or during the operation of a roller and a touch roller.
When an operation failure occurs in any of these operations in a conventional banding packing machine, it is necessary to stop all driving operations at once. The cam shaft must then be manually rotated to perform a banding operation. Specifically, in order to determine whether or not related members are set in their proper positions, the cam shaft must be rotated to each of its original position, a reverse rotation start position, a tightening start position, a normal rotation start position and the like on the cam shaft.
However, it is time and labor intensive to manually rotate the cam to each position and confirm an accurate positional relationship. Furthermore, it is difficult to decide whether or not a stop position is reached after the manual rotation is in a normal position.
In view of the foregoing, it is an object of the present invention to provide a controller in a banding packing machine which can regulate an operation distance by a link operation, and can easily correct a shift from the predetermined, correct timed cycle.
In order to attain this object, the present invention provides a controller in a banding packing machine, comprising:
a cam shaft which is rotated upon receipt of force from a driving source;
a plurality of cams provided on the cam shaft;
a timing plate provided on the cam shaft, said timing plate having a hole formed thereon which corresponds to a predetermined position so that a rotation position of the cam shaft can be detected; and
a detecting means for detecting that the hole formed on the timing plate has reached the predetermined position, and
an inching mode which stops the rotation of the cam shaft when the detecting means detects the hole formed on the timing plate.
With such a structure, it is possible to ascertain whether or not a related member is in its proper predetermined position by setting the inching mode to occur when the hole formed on the timing plate reaches a predetermined position. In the case when the related member does not have a predetermined positional relationship, it is preferable that the power source be turned off a single time to regulate the position.
It is preferable that the following two modes be switchable: (1) the inching mode for stopping the rotation of the cam shaft when the detecting means detects the hole of the timing plate; and (2) the operation mode for causing the detecting means to detect the hole of the timing plate, thereby driving the cam shaft in a normal cycle.
If the inching mode and the operation mode can be thus switched, the inching mode is set before a first operation is carried out and it is ascertained whether or not the inching mode is set in the normal condition. If the inching mode is set in the normal condition, the operation mode may be exactly set to carry out a continuous operation. On the other hand, if the positional relationship is not accurate, it is preferable that the position regulation be performed again and the operation mode then be set.
As described above, when the inching mode is set, the controller in the banding packing machine in accordance with the present invention makes it possible to determine, at each time, whether or not the positional relationship of each member is set in a correct position.
Accordingly, it is possible to easily adjust the positional relationship between the members.
These objects as well as other objects, features and advantages of the present invention will become more apparent to those skilled in the art from the following description with reference to the accompanying drawings.